A corrosion-resistant, magnetic pump typically includes a propeller contained within a fluid containment cavity for permitting a liquid, typically a corrosion-inducing fluid, to be propelled into the pump, through the cavity and then out of the pump. The containment cavity prevents the exposure of the corrosion-inducing fluid to other components of the pump outside the containment cavity for extending the life of the pump.
A motor is positioned outside the containment cavity, and is attached to and rotates a drive magnet for providing a rotating magnetic field which passes through and into the containment cavity for inducing rotation to the propeller. A driven magnet, which is attached to the propeller, is positioned inside the containment cavity for receiving the rotating magnetic flux, in which the magnetic interaction causes the driven magnet to rotate simultaneously with the drive magnet. This, in turn, causes the propeller to rotate for propelling the fluid through the cavity. The drive and driven magnets are typically permanent magnets made of neodymium-iron-boron (NdFeB) or samarium-cobalt (Sm-Co). Therefore, due to the fact that the driven magnet is exposed to the corrosion-inducing fluid, the driven magnet is typically coated with a corrosion-resistant, synthetic resin, such as that disclosed in U.S. Pat. No. 4,613,289, for extending the life of the magnet.
Although the presently known and utilized pump is satisfactory, it is not without drawbacks. The magnetic coupling between the drive and driven magnets is inefficient because they are spaced apart due to the thickness of the wall of the containment cavity. This causes the motor to consume more power to compensate for this inefficiency
Consequently, a need exists for improvements in the construction and mode of operation of the pump so as to overcome the above-described drawbacks.